MULTI-STROKE HYBRID PROPULSION SYSTEM
First Claim
1. A method of operating a hybrid propulsion system for a vehicle including an internal combustion engine, a generator, and an energy storage device, the method comprising:
- during a first condition, operating the engine in a two stroke cycle to produce a first engine output and charging the energy storage device by absorbing a first amount of the first engine output at the generator; and
during a second condition, operating the engine in a four stroke cycle to produce a second engine output.
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Accused Products
Abstract
A hybrid propulsion system for a vehicle and method of operation are described. The hybrid propulsion system includes an internal combustion engine that may be operated in a multi-stroke mode, whereby the engine may be selectively operated in one of a two stroke cycle and a four stroke cycle depending on operating conditions. As one example, the two stroke cycle may be utilized to provide increased engine torque when a recharging operation of the on-board energy storage device is requested. In some examples, a transition from the four stroke cycle to the two stroke cycle may be performed while maintaining the transmission in the previously selected gear ratio in response to a requested increase in charging or a requested increase in wheel torque as requested by the vehicle operator.
29 Citations
20 Claims
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1. A method of operating a hybrid propulsion system for a vehicle including an internal combustion engine, a generator, and an energy storage device, the method comprising:
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during a first condition, operating the engine in a two stroke cycle to produce a first engine output and charging the energy storage device by absorbing a first amount of the first engine output at the generator; and during a second condition, operating the engine in a four stroke cycle to produce a second engine output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A hybrid propulsion system for a vehicle, comprising:
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an internal combustion engine configured to produce an engine output, said engine operatively coupled with one or more drive wheels of the vehicle via a transmission; a motor configured to produce a motor output, said motor operatively coupled with said one or more drive wheels of the vehicle; an energy storage device configured to selectively supply energy to the motor; a control system configured to; increase a level of propulsive effort provided to said one or more drive wheels during a lower state of charge of the energy storage device by reducing a number of strokes performed by the engine per combustion cycle to increase the engine output produced by the engine; and increase a level of propulsive effort provided to said one or more drive wheels during a higher state of charge of the energy storage device by increasing an amount of energy supplied to the motor from the energy storage device to increase the motor output produced by the motor. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method of operating a hybrid propulsion system for a vehicle, including an internal combustion engine, a generator, and an energy storage device, the method comprising:
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operating the engine to produce an engine output; selectively operating the generator to charge the energy storage device by absorbing an amount of the engine output; adjusting a number of strokes performed by the engine per combustion cycle in response to a state of charge of the energy storage device; and adjusting the amount of the engine output absorbed by the generator in response to the number strokes performed by the engine per combustion cycle. - View Dependent Claims (17, 18, 19, 20)
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Specification